1. Field
The present disclosure relates to a needle bar thread guide fixed to a lower end of a needle bar of a sewing machine.
2. Description of the Related Art
Sewing machines have conventionally been provided with a needle bar thread guide which is fixed to a lower end of a needle bar to guide a needle thread caught on a needle thread take-up to an eye of a sewing needle along the needle bar. An operator causes a needle thread to pass through the needle bar thread guide before sewing, so that the needle thread can be prevented from uselessly swinging near the lower end of the needle when the needle bar is moved up and down. Then, the needle thread can easily be passed through the needle bar thread guide fixed to the lower end of the needle bar. Moreover, various proposed types of needle bar thread guides can keep the needle thread caught by the needle bar thread guide so that the needle thread is not easily detached.
JP-A-2004-236673 discloses, as a conventional example, a needle bar thread guide for a sewing machine, which comprises an upper first needle bar thread guide and a lower second needle bar thread guide both formed integrally with each other substantially into a reversed C-shape so that a needle bar connecting stud is clamped between the needle bar thread guides. The first needle bar thread guide includes a first thread guiding part formed in a right half thereof into a curved shape and a first threading part formed in a left half thereof so as to be retreated rearward. The second needle bar thread guide includes a second thread guiding part inclined obliquely rearward and extending horizontally and a second threading part continuous to the second thread guiding part.
According to the conventional construction, when the needle bar thread guide is to be threaded with a needle thread by a threading mechanism, the needle thread is caused to pass through the first thread guide part to be caught on the first threading part, whereby the first threading part is threaded. The needle thread is then guided rearward by the second thread guiding part of the second needle bar thread guide thereby to be caught on the second threading part, whereby the second threading part is threaded. In this case, the first and second thread guiding parts intersect with each other. Accordingly, when the first and second threading parts have been threaded with the needle thread, the needle thread cannot easily be detached from the first and second thread guiding parts.
In the above-described conventional example, however, the first thread guiding part protrudes forward relative to the second needle bar thread guide, and moreover, the first and second threading parts have opening directions different from each other. Accordingly, although the needle thread cannot easily disengage from the first and second thread guiding parts, the first needle bar thread guide having the first thread guiding part is vertically spaced away from the second needle bar thread guide having the second thread guiding part with the needle bar connecting stud being clamped therebetween. As a result, when the needle thread hops or jumps while being moved from the needle thread take-up toward the needle eye during sewing, thereby swinging widely, there is a low possibility that the needle thread may disengage from the needle bar thread guide.
Meanwhile, since the first thread guiding part of the first needle bar thread guide protrudes forward relative to the second needle bar thread guide, the needle bar thread guide cannot be threaded only by moving the needle thread linearly leftward when the operator manually threads the needle bar thread guide without using the threading mechanism. In this case, the needle thread needs to be moved leftward for the threading purpose while being circled forward in a large way. Thus, the threading operation is troublesome and the sewing machine lacks in the operability. Moreover, when the needle thread is to be disengaged from the needle bar thread guide, an operation reverse to the threading operation needs to be carried out, whereupon the sewing machine also lacks in the operability regarding an operation of unthreading the needle bar thread guide.